Date: Thu, 5 Mar 1998 09:09:14 -0600 (CST) From: "Richard M. Neswold" <neswold@fnal.gov> To: Peter van Heusden <pvh@leftside.wcape.school.za> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Detecting state of PPP Message-ID: <Pine.BSF.3.96.980305090154.4978B-100000@spiv.fnal.gov> In-Reply-To: <Pine.BSF.3.95.980305071307.15655F-100000@leftside.wcape.school.za>
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On Thu, 5 Mar 1998, Peter van Heusden wrote:
> How does one go about writing a program to check if a PPP link is up or
> down? I'm running PPP in -auto mode, and I'd like to be able to tell
> whether the PPP link is actually up (i.e. the modem connection is in
> place) at any particular time. Unfortunately, the flags on tun0 stay the
> same (0x8051 on my system) whether the modem is connected or not. What
> should I be looking at?
If you're looking for a way to do it in a script, I've found two successful
methods. Both methods use 'ifconfig' to check the state.
The first method is in Perl. The following test works on my system:
if (index(`ifconfig -l -u`, "tun0") > -1) {
... this code executes when 'tun0' is active...
}
I use a different method in my crontab file. My cron job to periodically
grab the latest sources has this command (I took out the full paths to make
it fit on one line):
ifconfig -l -u | grep -q tun0 && cvsup -L 1 -g /etc/supfile
This way, I only grab the sources if my connection is active.
You can test for "down" interfaces by replacing the -u option with -d.
Hope this helps...
Rich
------------------------------------------------------------------------
Richard Neswold, Accelerator Div./Controls Dept | neswold@fnal.gov
Fermilab, PO Box 500, MS 347, Batavia, IL 60510 | voice (630) 840-3454
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